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des.h
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1 /*
2  * DES encryption/decryption
3  * Copyright (c) 2007 Reimar Doeffinger
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVUTIL_DES_H
23 #define AVUTIL_DES_H
24 
25 #include <stdint.h>
26 
27 struct AVDES {
28  uint64_t round_keys[3][16];
30 };
31 
32 /**
33  * @brief Initializes an AVDES context.
34  *
35  * @param key_bits must be 64 or 192
36  * @param decrypt 0 for encryption/CBC-MAC, 1 for decryption
37  */
38 int av_des_init(struct AVDES *d, const uint8_t *key, int key_bits, int decrypt);
39 
40 /**
41  * @brief Encrypts / decrypts using the DES algorithm.
42  *
43  * @param count number of 8 byte blocks
44  * @param dst destination array, can be equal to src, must be 8-byte aligned
45  * @param src source array, can be equal to dst, must be 8-byte aligned, may be NULL
46  * @param iv initialization vector for CBC mode, if NULL then ECB will be used,
47  * must be 8-byte aligned
48  * @param decrypt 0 for encryption, 1 for decryption
49  */
50 void av_des_crypt(struct AVDES *d, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt);
51 
52 /**
53  * @brief Calculates CBC-MAC using the DES algorithm.
54  *
55  * @param count number of 8 byte blocks
56  * @param dst destination array, can be equal to src, must be 8-byte aligned
57  * @param src source array, can be equal to dst, must be 8-byte aligned, may be NULL
58  */
59 void av_des_mac(struct AVDES *d, uint8_t *dst, const uint8_t *src, int count);
60 
61 #endif /* AVUTIL_DES_H */